The present invention relates to a method for producing an individual-segment rotor for an electric machine. The present invention further relates to a corresponding individual-segment rotor.
Individual-segment rotors for electric motors with flux concentration are characterized in that the rotor is provided with permanent magnets arranged in a star-shaped manner and the intermediate space between the individual permanent magnets in each case is filled by a ferromagnetic individual segment. Such an individual segment is generally produced as a laminated core and therefore may be denoted as a laminated core segment. The individual laminated core segments are, if possible, not connected together.
The construction and production of an electric motor with magnets in flux concentration requires specific techniques. In particular, the construction should be scatter-resistant and suitable for mass production. Since a scatter-resistant construction generally requires the use of individual laminated segments, i.e. laminated core segments, and thus involves a higher production cost, such a construction hinders a mass production process.
Previous embodiments of corresponding rotors were a compromise between individual segments, on the one hand, and rotor laminations, on the other hand, which are connected together. With complete rotor laminations it is achieved that the laminated rotor core is able to be produced mechanically in a more stable and simple manner but a portion of the flux of the magnets is short-circuited. This is made possible, for example, by stamped and stacked rotor cores in which the inner separating bridges are kept at defined spacings. Individual segments as are disclosed, for example, in the post-published European patent application EP 12 159 917.9 provide the advantage that a short circuit is not produced. However, the number of components and thus the assembly and production cost increases.
Moreover, in an individual-segment rotor with flux concentration the rotor lamination has to be constructed separately by means of “non-magnetic” material (relative permeability μr less than 5) between each pole. This leads to a greater number of individual segments which have to be joined together. Problems occur here due to the complicated production of the individual segments and the complicated joining-together of the individual segments. Moreover, separate flux guidance has to be implemented by the non-magnetic material. Furthermore, problems occur with regard to the positioning and retention of the magnets and the torque transmission.
Previous embodiments were a compromise between individual segments and rotor laminations which are connected together. Thus it is achieved that the rotor core is able to be produced mechanically in a more stable and simple manner but a portion of the flux of the magnets is short-circuited. This is made possible, for example, by stamped and stacked rotor cores in which the inner separating bridges are always maintained.